[Coco] [off-topic] cabling problems

William Astle lost at l-w.ca
Wed Apr 18 21:20:13 EDT 2012


On 12-04-18 05:14 PM, Mark Ormond wrote:
>>>>> He has a 180 foot cable which is 80 feet beyond spec for 100BaseT (100Mbps ethernet)
>
> Actually the spec is 100M (meters) or around 330 feet.

I stand corrected. I do seem to recall that in a half duplex setting the 
effective limit is shorter due to collision detection and signal 
propagation speed, admittedly not a problem with modern hardware.

That said, kinks in the cable, interference sources, and dodgy cable 
ends could still cause the signal to fade out over the length of the 
cable even if a cable tester says continuity is good, something that 
becomes more noticeable as cable length increases.

>
>
> Later,
> dabone
>
> -----Original Message-----
> From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On Behalf Of William Astle
> Sent: Wednesday, April 18, 2012 6:48 PM
> To: coco at maltedmedia.com
> Subject: Re: [Coco] [off-topic] cabling problems
>
> On 12-04-18 04:07 PM, Frank Swygert wrote:
>> The shielded under ground cable I bought has a foil liner, so the
>> aluminum foil idea should work. The foil must be grounded to the cable
>> though. Phone wire is generally twisted pair. That shields the phone
>> signal, but I don't know if it does anything for other things near it.
>
> I thought the twisted part was to keep the transmission line effect going  and to keep the wires together rather than shielding. The telephone signal shouldn't be a problem - running telephone along with network in the same conduit is very common. Also, the signals in question are very different frequencies - telephone being audio frequencies while the network signal is in the MHz range.
>
> I don't know if this was mentioned - I haven't been following the thread closely enough, but here goes:
>
> He has a 180 foot cable which is 80 feet beyond spec for 100BaseT (100Mbps ethernet) so he could be having enough signal loss over that insufficient signal makes it to the receiver, especially if there is any interference, kinks, or dodgy ends.
>
> That said, the length restriction is more critical on half-duplex operation than full duplex. I assume full duplex operation here given that I haven't seen any router boxes that weren't also full switches.
>
>>
>> I suppose you already have the cable installed from the sound of things.
>> Next time test the cable before pulling! You might just have one wire
>> out of place...
>>
>> --------------
>> Date: Tue, 17 Apr 2012 22:17:01 -0300
>> From: Paulo Lindoso<paulo.lindoso at gmail.com>
>>
>> Hi List,
>>
>> Checked out Frank's idea and hooked a small hub... Didn't work...
>>
>> One thing I noticed though... when I plugged the cable, it seemed to me
>> that the indicator LED did lit up a bit... Could that be an indication
>> of interference of sorts?
>>
>> As I mentioned it is a 180-feet long cable, directly wired, linking my
>> wireless router (a standard WRT54G with dd-wrt installed) to my studio,
>> which is a small extension outside my house.
>>
>> Inside the house, it actually shares its way with a telephone wire and
>> my cable TV coax cable... Now the coax cable is obviously shielded, so I
>> would not imagine any interference from there, but the telephone line is
>> generally UNshielded and powered at 48VDC plus the carrier signal...
>> Could that mess up the network signal?
>>
>> I will try this weekend to insulate and/or separate its way and will
>> post back... Let's see.
>>
>> Has anybody ever tested the "urban legend" of insulating a cable with
>> aluminum foil? Does it actually work?
>>
>> Thanks a lot for all useful hints and comments so far!
>>
>
>
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